Discount Calculator
Find the final price after a discount and exactly how much you save. Supports a second stacked discount (like "30% off + extra 10% at checkout") — which is never as big as it sounds, and this calculator shows why.
How to use this calculator
- Enter the original price from the tag.
- Enter the advertised discount percentage.
- If there's an extra discount (coupon, checkout offer), add it — it applies to the reduced price.
- Press Calculate to see the final price, your savings, and the true combined discount.
Formula used
Stacked discounts multiply rather than add: 30% + 10% is not 40% off. The second discount applies to the already-reduced price, so the effective total here is 1 − (0.70 × 0.90) = 37% off.
Example calculation
A jacket priced 1,999 with 30% off plus an extra 10% coupon:
After 30%: 1,999 × 0.70 = 1,399.30. After extra 10%: × 0.90 = 1,259.37. You save 739.63 — an effective 37% discount, not 40%.
How store discounts really work
A discount reduces the price by a percentage of the original. The math is simple, but retailers layer offers in ways designed to feel bigger than they are: stacked percentages multiply (30% + 10% = 37%, not 40%), "up to X% off" usually applies to a few items, and inflated "original" prices make ordinary prices look like deals.
The number that matters is the final price and what you save in currency, not the percentage on the banner. Calculating it in seconds — especially during sales events — is the difference between a genuine bargain and clever framing.
Why use this calculator?
- Know the exact checkout price before you get there — no surprises at the till.
- See the true combined discount when offers stack, which is always less than the sum.
- Compare deals across stores by final price instead of headline percentages.
Frequently asked questions
How do I calculate 20% off a price?
Multiply the price by 0.80 (that is, 1 − 0.20). A 500 item at 20% off costs 500 × 0.80 = 400. Mental shortcut: find 10% by moving the decimal (50), double it (100), subtract.
Is 30% off plus an extra 10% the same as 40% off?
No. The extra 10% applies to the already-discounted price, so the combined discount is 1 − (0.70 × 0.90) = 37%. Stacked discounts always total less than their sum.
How do I find the original price from a sale price?
Divide the sale price by (1 − discount). If something costs 350 after 30% off, the original was 350 ÷ 0.70 = 500. Don't add 30% of 350 back — that gives the wrong answer.
Does the discount apply before or after tax?
Discounts almost always apply to the pre-tax price, and sales tax or GST is then charged on the discounted amount. So your final total = discounted price × (1 + tax rate).